1. Field of the Invention
The present invention relates to a fire alarm system.
2. Description of the Related Art
Conventionally, in a fire alarm system consisting of fire receivers connected to each other by a LAN, fire detection information of fire receivers is shared between each of the fire receivers connected by the LAN.
In addition, in the conventional fire alarm system, as a plurality of terminal apparatuses connected to a fire receiver, controlled apparatuses such as area sound apparatuses and smoke preventing and exhausting apparatuses which operate in correspondence with an issue of an alarm of a fire sensor that detect a fire are connected to the same fire receiver. The linkage therebetween is made by the unit of a receiver.
In addition, a fire alarm system is configured such that a plurality of fire receivers are connected by a LAN (Local Area Network), respectively, and share data by exchanging data signals (hereinafter referred to simply as signals). In this case, there are two ways in which a signal is transmitted. One is the case in which a fire receiver transmits a signal to another fire receiver. The other is the case in which a fire receiver transmits a signal to all the other fire receivers connected to the LAN, which is a so-called global transmission. The global transmission will be specifically described in this specification. When a fire receiver carries out the global transmission, the other fire receivers transmit response data signals (hereinafter referred to as response signals) in order to indicate that a signal of the global transmission has been accurately received.
FIGS. 9a to 9c illustrate conventional signals that are transmitted over a LAN. A description will be made assuming that five fire receivers are connected to the LAN in FIGS. 9a to 9c. FIG. 9a shows that each fire receiver independently transmits a response signal to a fire receiver #1 in response to a global fire signal that is transmitted by the fire receiver #1 designating all the other fire receivers as destinations of transmission. In this case, five signals (one fire signal and four response signals) are transmitted over the LAN. FIG. 9b shows that the fire receiver #1 transmits a global fire signal and then a fire receiver #2 also transmits a global fire signal. Here, a fire signal is given priority over a response signal. Thus, the tire signal is transmitted by the fire receiver #2 before all the fire receivers finish transmitting response signals in response to the fire signal transmitted by the fire receiver #1. Then, since there is not specifically any order of priority for each response signal, response signals responding to the fire signal transmitted by the fire receiver #2 may be transmitted earlier than response signals responding to the fire signal transmitted by the fire receiver #1. In this case, ten signals (two fire signals and eight response signals) are transmitted over the LAN. FIG. 9c shows that each fire receiver transmits a response signal in response to each global fire signal transmitted by each of the five fire receivers. In this context, for simplicity of a description, each response signal is transmitted to the LAN in good order. However, since there is not specifically any order of priority for each response signal actually as described above, each response signal may not be transmitted in good order. In this case, twenty-five signals (five fire signals and twenty response signals) are transmitted over the LAN.
In addition, a repeater of the conventional fire alarm system cannot cause controlled apparatuses such as area sound apparatuses and smoke preventing and exhausting apparatuses to be driven by a power source superimposed over a signal line from a fire receiver. Therefore, the repeater receives an activation signal transmitted by a fire receiver, causes a relay to operate based on the activation signal and supplies an external power to the controlled apparatuses, thereby activating the controlled apparatuses.
In addition, the repeater of the conventional fire alarm system is provided with a disconnection monitoring circuit or the like in order to detect disconnection of a control line to which the controlled apparatuses are connected. For example, in the disconnection monitoring circuit, resistors are connected in parallel on the controlled apparatus side, a micro-current is always flown to the control line and disconnection is detected according to a variation of the current, whereby disconnection of the control line is monitored.
However, in recent years, since buildings have become larger and more complicated, if a building is divided into two ridge sections, for example, it is sufficient to monitor a fire in each ridge section in many cases when a plurality of fire receivers are installed to configure a fire alarm system. Thus, since fire detection information is shared by all fire receivers connected to a LAN in the conventional fire alarm system, for example, an occurrence of a fire in one ridge section may be notified to the other ridge section and the other ridge section where a fire has not occurred is carelessly disordered.
In addition, as buildings become larger, it is likely that controlled apparatuses such as smoke exhausting outlets and smoke exhausting fans and a series of fire doors are connected to different fire receivers. However, in the conventional fire alarm system, since the linkage of the controlled apparatuses to an issue of an alarm of a fire sensor is made by the unit of a fire receiver, the controlled apparatuses cannot operate in correspondence with the issue of the alarm by the fire sensors among different fire receivers.
In addition, here, it is assumed that, for example, sixty-four fire receivers are connected to each other by a LAN. When one fire receiver transmits a global fire signal, the remaining sixty-three fire receivers transmit response signals responding to the fire signal (the total number of signals is sixty-four). subsequently, when another fire receiver transmits a global fire signal, the remaining sixty-three fire receivers also transmit response signals. In this way, if all the fire receivers transmit fire signals one after another, the total of 4096 (=64xc3x9764) signals are exchanged over the LAN. Actually, when an alarm is sounded to warn a fire, it is normally for an area where an issue of an alarm is required but all alarms may be sounded all at once if necessary. In this case, a state of signals over the LAN is the same as the above-mentioned state.
Each fire receiver is set such that a signal of fire information is given priority over other signals in transmission even among such a large volume of signals. However, if a large volume of signals is transmitted, since it is highly likely that signals collide with each other over the LAN and data is collapsed, re-transmission processing of signals is required. In addition, processing after receiving the signals is complicated. Due to such useless signals, a fire receiver satisfying a processing capacity that allows for a worst result is required.
In addition, the repeater of the conventional fire alarm system causes the relay to operate, thereby supplying an external power to controlled apparatuses to activate the controlled apparatuses. However, operation of a relay contact is not detected because it is assumed that the contact normally operates when the relay is caused to operates
Thus, if the relay contact is not in operation in spite of the fact that the relay is caused to operate, there is a problem where it is likely that controlled apparatuses are not actually activated in a state in which a fire receiver determines that the controlled apparatuses are activated.
Therefore, it is possible to confirm operation of the relay by separately providing a circuit for confirming operation of a relay and using the circuit to monitor a variation of a voltage or the like on the controlled apparatus side at the time when the relay is caused to operate. However, this makes the circuit of the repeater complicate and increases the number of components of the repeater.
In addition, a power source superimposed over a signal line from a fire receiver is used as an operation power source of each circuit including that for driving the relay in the repeater. When high and low of a voltage are repeated by a transmission signal transmitted through the signal line, there is a problem where, if the relay is caused to operate in the low state, the relay may not respond because a voltage level for causing the relay to operate is too low.
The present invention has been devised in order to solve such problems, and it is an object of the present invention to provide a fire alarm system with which information can be shared among a plurality of fire receivers, which are connected to each other by a LAN, for each unit of a group of fire receivers, and controlled apparatuses can operate in accordance with an issue of an alarm by a fire sensor among different fire receivers.
In addition, it is an object of the present invention to provide a fire alarm system that can reduce the number of signals to be exchanged over a LAN as far as possible.
Further, it is an object of the present invention to provide a repeater that can detect operation of a relay contact by a simple circuit without increasing the number of components thereof.
A fire receiver according to the present invention is provided with, in a fire receiver to which a plurality of fire sensors and controlled apparatuses, which is controlled in correspondence with an issue of an alarm of the fire sensor, are connected, an interface for LAN access for connecting to other fire receivers by a LAN, means for, when the fire sensors issue an alarm, transmitting the fire information together with a group number set in advance over the LAN, and means for, upon receiving fire information transmitted from other fire receivers via the LAN, displaying only the fire information of the same group number.
Further, a fire receiver according to the present invention is provided with means for, when a special group number is set as a group number, displaying all pieces of fire information upon receiving the fire information transmitted from the other fire receivers via the LAN.
Further, in a fire receiver according to the present invention, a special group number can be set as a group number and the fire receiver is provided with means for displaying fire information upon receiving the fire information transmitted from fire receivers of the special group number via the LAN.
Further, a fire receiver according to the present invention is provided with, in a fire receiver to which a plurality of fire sensors and controlled apparatuses, which is controlled in accordance with an issue of an alarm of the fire sensor, are connected, an interface for LAN access for connecting to other fire receivers by a LAN, storing means in which information on interlocking relation between the fire sensors and the controlled apparatuses as well as interlocking relation between the fire sensors and controlled apparatuses of other fire receivers is stored, means for, when the fire sensors issue an alarm, outputting activation information of controlled apparatuses to be interlocked, and transmitting activation information to the other fire receivers over the LAN at the same time based on the information stored in the storing means, and means for activating controlled apparatuses designated by the activation information upon receiving the activation information transmitted from the other fire receivers via the LAN.
Further, a fire receiver according to the present invention is provided with, in a fire receiver to which a plurality of fire sensors and controlled apparatuses, which is controlled in accordance with an issue of an alarm of the fire sensors, are connected, an interface for LAN access for connecting to other fire receivers by a LAN, storing means in which zone information set for each of the fire sensors and the controlled apparatuses and common zone information to controlled apparatuses of the other fire receivers are stored, means for, when the fire sensors issue an alarm, outputting activation information of controlled apparatuses to be interlocked in an identical zone, and transmitting the common zone information over the LAN at the same time based on the zone information stored in the storing means, and means for activating controlled apparatuses of an identical common zone based on the zone information stored in the storing means upon receiving the common zone information transmitted from the other fire receivers via the LAN.
Other objects and features of the present invention will be apparent from the following descriptions taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.